Reactive mesogen formulation with conductive additive

ABSTRACT

The invention relates to a reactive mesogen (RM) formulation comprising a conductive additive, to a polymer film obtained thereof, and the use of the RM formulation and polymer film in optical or electrooptical components or devices, like optical retardation films for liquid crystal displays (LCDs).

FIELD OF THE INVENTION

The invention relates to a reactive mesogen (RM) formulation comprisinga conductive additive, to a polymer film obtained thereof, and the useof the RM formulation and polymer film in optical or electroopticalcomponents or devices, like optical retardation films for liquid crystaldisplays (LCDs).

BACKGROUND AND PRIOR ART

RMs and mixtures of RMs can be used to make optical films, likecompensation, retardation or polarisation films, e.g. for use ascomponents of optical or electrooptical devices like LC displays,through the process of in-situ polymerisation. The optical properties ofthe films can be controlled by various factors, such as mixtureformulation or substrate properties.

The films are usually prepared by coating a solution of an RM or of anRM mixture on a substrate, removing the solvent, aligning the RMs intothe desired orientation, and polymerising the coated and aligned RMs insitu by exposure to heat or actinic radiation, for example to UVradiation, and optionally removing the polymerised film from thesubstrate.

However, coating of a substrate with a solution containing RMs can leadto a build up of static charge if the solution is not conducting. Thiscan lead to an electrostatic discharge by arcing, and, if the solvent isflammable, result in a fire or explosion. This hazard can be reduced byengineering solutions such as the use of tinsel and electrostaticneutralization bars. However, the rapid pumping of a non-conductiveflammable fluid to a coating head can also lead to electrostaticdischarge.

For example, a typical manufacturing method for such polymerised RM filmproducts is roll to roll processing of a plastic substrate, in whichcoating of a reactive mesogen solution is an integral step. During theproduction steps there is the potential for build-up of electric charge,which must be discharged to prevent the danger of uncontrolleddischarge, or the potential for defects or damage of the final product.

Moreover, the build up of static charge can lead to unwanted effects inpolymerised optical films such as uneven coating, which can be visuallyobserved and is often referred to as “mura”.

It is generally known that such electrostatic charge build up can bemitigated if conducting solvents are used (see e.g. Matthew R. Giles inOrganic Process Research & Development 2003, 7, 1048-1050), however,this greatly reduces the choice of solvents available to the formulator.This is especially disadvantageous because RMs are not commonly solublein polar solvents. Besides, it is also possible that such solvents arenot compatible with the substrates onto which the solution should becoated.

This invention has the aim of providing improved RM formulations andmethods which enable the preparation of polymer films with reduced, oreven without, build up of static charge, in order to avoid drawbacks andrisks like electrostatic discharge by arcing, uneven coatings andoptical defects like mura, while retaining the advantageous RM and filmproperties such as good coatability, good alignment and high durability.Other aims of the invention are immediately evident to the expert fromthe following description.

The inventors of the present invention found that these aims can beachieved by adding certain conductive additives to the RM formulation.Thereby the static build up when coating the mixture on a substrate isreduced, whilst other properties such as good coatability, alignment anddurability are retained.

WO 2003/083523 discloses that polar additives can be added to liquidcrystal (LC) mixtures, however their role is to induceelectro-hydrodynamic instability in a bistable LC mode. The additivesare therefore not polymerisable. WO 2008/110342 also describes the useof highly polar additives to enhance the properties of an RMformulation, but in this case, the additives are magnetic orparamagnetic particles. Also the formulations described in WO2008/110342 are designed for inkjet printing rather than solutioncoating. WO 2008/110316 discloses the use of similar polar pigments inRM formulations that can be processed to prepare polarisation selectivescattering devices for security devices. WO 2008/110317 describes thepreparation of inkjettable RM formulations, but wherein the polaradditives are pigmented or polymer additives. US 2011/0240927 describesa formulation that contains a direactive RM and a polar additive, andcan be processed to make a transparent conducting layer as analternative to the ITO electrodes that ate commonly used as electrodesfor LC display (LCD) manufacture. However, in this case, the amount ofRM is limited to 20% and the formulation does not give a film that actsas a birefringent retardation film. In this case, the additives arePEDOT/PSS (poly-3,4-ethylenedioxy-thiophene/polystyrene sulphonate),which are not soluble in the solvents commonly used for RM formulations.However, the above-mentioned documents do neither disclose nor suggestthe RM formulations, methods and uses as claimed in the presentinvention.

SUMMARY OF THE INVENTION

The invention relates to a formulation comprising >50% of one or morepolymerisable mesogenic compounds, and further comprising one or moreconductive additives, which are preferably selected from reactiveorganic compounds and/or ionic organic compounds.

The invention further relates to a polymer film comprising or consistingof a polymerised RM formulation as described above and below.

The invention further relates to a polymer film obtained by polymerisinga layer of an RM formulation as described above and below, preferablywherein the RMs are aligned, and preferably at a temperature where theRM formulation exhibits a liquid crystal phase.

The invention further relates to the use of an RM formulation or polymerfilm as described above and below in polymer films, preferably for useas optical films, antistatic protection sheets or electromagneticinterference protection sheets.

The invention further relates to the use of an RM formulation or polymerfilm as described above and below in optical, electrooptical orelectronic components or devices.

The invention further relates to an optical, electrooptical orelectronic device or a component thereof, comprising an RM formulationor polymer film as described above and below.

Said components include, without limitation, optical retardation films,polarizers, compensators, beam splitters, reflective films, alignmentlayers, colour filters, antistatic protection sheets, or electromagneticinterference protection sheets, polarization controlled lenses forautostereoscopic 3D displays, and IR reflection films for windowapplications.

Said devices include, without limitation, electrooptical displays,especially liquid crystal displays, autostereoscopic 3D displays,organic light emitting diodes (OLEDs), optical data storage devices, andwindow applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the retardation versus viewing angle for polymer filmsprepared in accordance with example 2.

FIG. 2 shows the retardation versus viewing angle for polymer filmsprepared in accordance with example 3.

FIGS. 3, 4 and 5 show the retardation durability (retardation drop vs.temperature) for polymer films prepared in accordance with example 4.

DEFINITIONS OF TERMS

The term “liquid crystal”, “mesomorphic compound, or “mesogeniccompound” (also shortly referred to as “mesogen”) means a compound thatunder suitable conditions of temperature, pressure and concentration canexist as a mesophase or in particular as a LC phase. Non-amphiphilicmesogenic compounds comprise for example one or more calamitic,banana-shaped or discotic mesogenic groups.

The term “calamitic” means a rod- or board/lath-shaped compound orgroup. The term “banana-shaped” means a bent group in which two, usuallycalamitic, mesogenic groups are linked through a semi-rigid group insuch a way as not to be collinear.

The term “discotic” means a disc- or sheet-shaped compound or group.

The term “mesogenic group” means a group with the ability to induceliquid crystal (LC) phase behaviour. Mesogenic groups, especially thoseof the non-amphiphilic type, are usually either calamitic or discotic.The compounds comprising mesogenic groups do not necessarily have toexhibit an LC phase themselves. It is also possible that they show LCphase behaviour only in mixtures with other compounds, or when themesogenic compounds or the mixtures thereof are polymerised. For thesake of simplicity, the term “liquid crystal” is used hereinafter forboth mesogenic and LC materials.

A calamitic mesogenic compound is usually comprising a calamitic, i.e.rod- or lath-shaped, mesogenic group consisting of one or more aromaticor alicyclic groups connected to each other directly or via linkagegroups, optionally comprising terminal groups attached to the short endsof the rod, and optionally comprising one or more lateral groupsattached to the long sides of the rod, wherein these terminal andlateral groups are usually selected e.g. from carbyl or hydrocarbylgroups, polar groups like halogen, nitro, hydroxy, etc., orpolymerisable groups.

A discotic mesogenic compound is usually comprising a discotic, i.e.relatively flat disc- or sheet-shaped mesogenic group consisting forexample of one or more condensed aromatic or alicyclic groups, like forexample triphenylene, and optionally comprising one or more terminalgroups that are attached to the mesogenic group and are selected fromthe terminal and lateral groups mentioned above.

For an overview of terms and definitions in connection with liquidcrystals and mesogens see Pure Appl. Chem. 73(5), 888 (2001) and C.Tschierske, G. Pelzl and S. Diele, Angew. Chem. 2004, 116, 6340-6368.

The term “reactive mesogen” (RM) means a polymerisable mesogenic orliquid crystalline compound, which is preferably a monomeric compound.

Polymerisable compounds with one polymerisable group are also referredto as “monoreactive” compounds, compounds with two polymerisable groupsas “direactive” compounds, and compounds with more than twopolymerisable groups as “multireactive” compounds. Compounds without apolymerisable group are also referred to as “non-reactive” compounds.

The term “ionic liquid (IL)” refers to organic salts that usually havemelting points below 373 K. Review articles on ionic liquids are, forexample, R. Sheldon “Catalytic reactions in ionic liquids”, Chem.Commun., 2001, 2399-2407; M. J. Earle, K. R. Seddon “Ionic liquids.Green solvent for the future”, Pure Appl. Chem., 72 (2000), 1391-1398;P. Wasserscheid, W. Keim “Ionische Flüssigkeiten—neue Lösungen für dieÜbergangsmetallkatalyse” [Ionic Liquids—Novel Solutions forTransition-Metal Catalysis], Angew. Chem., 112 (2000), 3926-3945; T.Welton “Room temperature ionic liquids. Solvents for synthesis andcatalysis”, Chem. Rev., 92 (1999), 2071-2083 or R. Hagiwara, Ya. Ito“Room temperature ionic liquids of alkylimidazolium cations andfluoroanions”, J. Fluorine Chem., 105 (2000), 221-227.

The term “polymerisable ionic liquid (PIL)” means an ionic liquid with apolymerisable group attached to the cation via a spacer group.

The term “spacer” or “spacer group”, also referred to as “Sp” below, isknown to the person skilled in the art and is described in theliterature, see, for example, Pure Appl. Chem. 73(5), 888 (2001) and C.Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.Unless stated otherwise, the term “spacer” or “spacer group” above andbelow denotes a flexible organic group, which in a polymerisablemesogenic compound (“RM”) connects the mesogenic group and thepolymerisable group(s).

The term “film” includes rigid or flexible, self-supporting orfree-standing films with mechanical stability, as well as coatings orlayers on a supporting substrate or between two substrates. “Thin film”means a film having a thickness in the nanometer or micrometer range,preferably at least 10 nm, very preferably at least 100 nm, andpreferably not more than 100 μm, very preferably not more than 10 μm.

The term “carbyl group” means any monovalent or multivalent organicradical moiety which comprises at least one carbon atom either withoutany non-carbon atoms (like for example —C≡C—), or optionally combinedwith at least one non-carbon atom such as N, O, S, P, Si, Se, As, Te orGe (for example carbonyl etc.). The term “hydrocarbyl group” denotes acarbyl group that does additionally contain one or more H atoms andoptionally contains one or more hetero atoms like for example N, O, S,P, Si, Se, As, Te or Ge. A carbyl or hydrocarbyl group comprising achain of 3 or more C atoms may also be linear, branched and/or cyclic,including spiro and/or fused rings.

DETAILED DESCRIPTION

In the RM formulations of the present invention the conductive additivesallow for an increase in conductivity. The increase of conductivity ofthe RM formulation enables the preparation of polymer films withreduced, or even without, build up of static charge during the filmforming process, and thereby avoids hazards like spontaneous andundesired electrostatic discharge by arcing. In addition, it reduces oravoids uneven coatings and optical defects like mura, while retainingthe advantageous RM and film properties such as good coatability, goodalignment and high durability.

In a first preferred embodiment of the present invention the conductiveadditives are ionic organic compounds, or organic salts, of the formulaC⁺A⁻, wherein C⁺ is an organic cation and A⁻ is an anion, for exampleselected from quaternary ammonium salts, phosphonium salts, imidazoliumsalts or other N-heterocyclic salts.

Many of these organic salts are also known as ionic liquids (IL). Ionicliquid molecules provide soft, bulky ions that have the ability todissociate in low dielectric constant liquids. Preferably, the anion hasa van der Waals volume of at least 80 A³.

In a second preferred embodiment the conductive additives are selectedfrom organic compounds that are both ionic and reactive, i.e. ionicorganic compounds comprising one or more polymerisable functionalgroups, or polymerisable ionic liquids (PIL). Preferably a polymerisableionic compound or PIL is used, where the cation is modified with apolymerisable group to incorporate soft, bulky ions into the polymerformed by the RM formulation. This is then copolymerised with the RMscontained in the RM formulation to form a polymer film.

In a third preferred embodiment of the present invention the conductiveadditives are selected from reactive organic compounds comprising one ormore polar groups which increases the conductivity of the RMformulation, and further comprising one or more polymerisable functionalgroups which can co-polymerise with the RMs forming a polymer network.

By careful selection of the additive, for example by selection of thetype of ionic components or polymerisable functional group, it can beachieved that the processing and properties of the RM formulation and ofthe final polymerised film, are unchanged or only slightly changed,compared to an RM formulation without a conductive additive.

The ionic organic compounds preferably contain an organic cation, verypreferably selected from the group consisting of ammonium, phosphonium,sulfonium, uronium, thiouronium, guanidinium, and heterocyclic cationssuch as imidazolium, pyridinium, pyrrolidinium, triazolium, morpholiniumor piperidinium cation.

Preferred heterocyclic cations are selected from the group consisting of

wherein the substituents R^(1′) to R^(4′) each, independently of oneanother, denote

-   -   a straight-chain or branched alkyl having 1-20 C atoms, which        optionally can be partially fluorinated, but not in α-position        to hetero-atom, and which can also include oxygen or/and sulfur        atoms in any positions in between carbon atoms, or    -   saturated, partially or fully unsaturated cycloalkyl having 5-7        C atoms, which may be substituted by alkyl groups having 1-6 C        atoms, and wherein the substituents R^(1′), R^(2′), R^(3′)        and/or R^(4′) together may also form a ring system, and, in case        of reactive compounds, one of the substituent R^(1′) to R^(4′)        may also denote a spacer group Sp that is linked to a        polymerisable functional group.

Preferably, the cation C⁺ is an alkyl substituted ammonium, pyridinium,pyrrolidinium or imidazolium group, very preferably atetraalkylammonium, tetraalkylphosphonium, N-alkylpyridinium,N,N-dialkylpyrrolidinium, 1,3-dialkylimidazolium or trialkylsulfoniumcation.

Very preferably the cation C⁺ is selected from the group consisting oftetraalkyl ammonium, tetraaryl ammonium, or mixed tetra alkyl-arylammonium, wherein the alkyl or aryl groups may be identical or differentfrom each other, furthermore heterocyclic ammonium, protonated alkyl oraryl ammonium or other nitrogen based ions such as dilauryl ammonium.Preferred examples include, without limitation, tetraalkylammonium,1-alkyl-3-methylimidazolium, 1-alkyl-2,3-dimethylimidazolium,N-alkyl-3-methyl-pyridinium, N-alkyl-3-hydroxypropyl-pyridinium,N-alkyl-3-hydroxymethyl-pyridinium, N-alkyl-4-dimethylamino-pyridinium,N-methyl-N-alkyl-pyrrolidinium, wherein “alkyl” denotes an alkyl grouphaving 1, 2, 3, 4, 5 or 6 C atoms.

The anion is preferably an inorganic anion, very preferably a halide,borate, imide, phosphate, sulfonate, sulfate, succinate, naphthenate orcarboxylate anion.

Very preferably the anion is selected from the group consisting ofhalides, hydrogensulfate, alkylsulfates, fluoroalkyl-phosphates,hexafluorophosphate, bis(trifluoromethylsulfonyl)imide, formate,trifluoroacetate, tetrafluoroborate, oxalatoborate, tetracyanoborate,dicyanamide, tricyanomethide, thiocyanate, methanesulfonate, triflate(trifluoromethane-sulfonate), nonaflate (nonafluorobutane-sulfonate),tosylate (toluene-sulfonate) and hydrogensulfate.

Most preferably the anion is selected from the group consisting of Cl⁻,Br⁻, I⁻, [HSO₄]⁻, [CH₃SO₄]⁻, [C₂H₅SO₄]⁻, [C₄H₉SO₄]⁻, [C₆H₁₃SO₄]⁻,[C₈H₁₇SO₄]⁻, [C₅H₁₁O₂SO₄]⁻, [(C₂F₅)₃PF₃]⁻, [PF₆]⁻, [N(SO₂CF₃)₂]⁻,[HCOO]⁻, [CF₃COO]⁻, [BF₄]⁻, [B(C₂O₄)₂]⁻, [B(CN)₄]⁻, [N(CN)₂]⁻,[C(CN)₃]⁻, [SCN]⁻, [CH₃SO₃]⁻, [CF₃SO₃]⁻, [C₄F₉SO₃]⁻, [CH₃C₆H₄SO₃]⁻.

Further preferred anions are selected from the group consisting of

-   chloride-   bromide-   iodide-   tetrafluoroborate-   tetracyanoborate (TCB)-   difluoro-dicyano borate-   fluoro-tricyano borate-   perfluoroalkyl-fluoro-dicyano borate-   pentafluoroethyl-fluoro-dicyano borate-   perfluoroalkyl-difluoro-cyano borate-   pentafluoroethyl-difluoro-cyano borate-   perfluoroalkyl-fluoro borate (FAB)-   perfluoroalkyl-alkoxy-dicyano borate-   alkoxy-tricyano borate-   methoxy-tricyano borate-   ethoxy-tricyano borate-   2,2,2-trifluoroethoxy-tricyano borate-   bis(2,2,2-trifluoroethoxy)-dicyano borate-   tetraphenylborate (TPB)-   tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (TFPB)-   tetrakis(4-chlorophenyl)borate-   tetrakis(4-fluorophenyl)borate-   tetrakis(pentafluorophenyl)borate-   tetrakis(2,2,2-trifluoroethoxy)borate-   bis(oxalato)borate-   bis(trifluoromethylsulfonyl)imide (NTF)-   bis(fluorosulfonyl)imide-   bis[bis(pentafluoroethyl)phosphinyl]imide (FPI)-   tris(trifluoromethylsulfonyl)methide-   (fluoroalkyl)fluorophosphate-   tris(pentafluoroethyl)trifluorophosphate (FAP)-   bis(pentafluoroethyl)tetrafluorophosphate-   (pentafluoroethyl)pentafluorophosphate-   tris(nonafluorobutyl)trifluorophosphate-   bis(nonafluorobutyl)tetrafluorophosphate-   (nonafluorobutyl)pentafluorophosphate-   hexafluorophosphate-   bis(fluoroalkyl)phosphinate-   bis(pentafluoroethyl)phosphinate-   bis(nonafluorobutyl)phosphinate-   (fluoroalkyl)phosphonate-   (pentafluoroethyl)phosphonate-   (nonafluorobutyl)phosphonate-   nonafluorobutane sulfonate (nonaflate) (NFS)-   trifluoromethanesulfonate-   trifluoroacetate-   methanesulfonate-   butanesulfonate-   butylsulfate-   hexylsulfate-   octylsulfate-   dicyanamide-   tricyanomethide-   thiocyanate-   hydrogensulfate-   trifluoroacetate-   tosylate-   docusates: (bis(2-2-ethyl hexyl) sulfosuccinate (AOT)-   naphthenates-   lauryl sulphate-   alkyl benzene sulfonates (dodecyl benzene sulfonates, linear and    branched)-   alkyl naphthalene sulfonate-   alkyl aryl ether phosphates-   alkyl ether phosphate-   alkyl carboxylates: stearate, octoates, heptanoate,    wherein preferably “alkyl” is C₁-C₂₀ alkyl, “fluoroalkyl” is    fluorinated C₁-C₂₀ alkyl, “perfluoroalkyl” is C₁-C₂ perfluoroalkyl,    and “aryl” is optionally substituted C₅-C₈-aryl, preferably benzene.

Examples of suitable and preferred anions of this group include, withoutlimitation, tetracyanoborate (TCB), tetraphenylborate (TPB),tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (TFPB),bis(trifluoromethylsulfonyl)imide (NTF),tris(pentafluoroethyl)trifluorophosphate (FAP),bis[bis(pentafluoroethyl)phosphinyl]imide (FPI), nonafluorobutanesulfonate (nonaflate) (NFS), (bis(2-2-ethyl hexyl) sulfosuccinate (AOT),pentafluoroethyl-dicyano-fluoro borate, methoxy-tricyano borate,ethoxy-tricyano borate and 2,2,2-trifluoroethoxy-tricyano borate.

Preferred fluoroalkyl phosphate anions (FAP-anions) include[PF₃(C₂F₅)₃]⁻, [PF₃(C₄F₉)₃]⁻, [PF₃(C₃F₇)₃]⁻, [PF₄(C₂F₅)₂]⁻,[PF₅(C₂F₅)]⁻,

Preferred fluoroalkyl-fluoro borate anions (FAB anions) include[B(CF₃)₄]⁻, B(C₂F₅)₄]⁻, [BF₃(CF₃)]⁻, [BF₃(C₂F₅)]⁻, [BF₃(i-C₃F₇)]⁻,[BF₂(CF₃)₂)₂]⁻, [BF₂(C₂F₅)₂]⁻, [BF₂(CF₃)₂]⁻, [BF(C₂F₅)₃]⁻, [BF(CF₃)₃]⁻oder [BF(CF₃)(C₂F₅)₂]⁻.

Preferred examples of ionic organic compounds are for exampletetra-n-butyl ammonium chloride, tetraoctyl ammonium bromide, benzyltridecylammonium benzene sulfate, diphenyl didodecyl ammoniumhexafluorophosphate, N-Methyl-N-trioctyl-ammoniumbis(trifluoromethylsulfonyl)imide, or mixtures thereof.

The reactive ionic organic compounds, or polymerisable ionic liquids, ofthe second preferred embodiment, hereinafter also referred to as“polymerisable ionic compounds”, are preferably selected of formula 1:

P¹-Sp-C⁺A⁻  1

wherein P¹ is a polymerisable group, Sp is a spacer group or a singlebond, C⁺ is a cation, and A⁻ is an anion.

Preferred compounds of formula 1 are selected of formula 1a-c:

P¹-Sp-[NR^(a)R^(b)R^(c)]⁺A⁻  1a

P¹-Sp-[PR^(a)R^(b)R^(c)]⁺A⁻  1b

P¹-Sp-[SR^(a)R^(b)R^(c)]⁺A⁻  1c

-   wherein P¹, Sp and A⁻ are as defined in formula 1,-   R^(a), R^(b), R^(c)C independently of each other denote    straight-chain, branched or cyclic alkyl with 1 to 25, preferably 1    to 10 C-atoms, wherein one or more CH₂ groups are optionally    replaced, in each case independently from one another, by —O—, —S—,    —NH—, —NR⁰—, —CO—, —CH═CH— or —C≡C— in such a manner that O and/or S    atoms are not linked directly to one another, and wherein one or    more H atoms may also be replaced by F, Cl, Br, I or CN, or two of    R^(a), R^(b) and R^(c) together with the N- P- or S-atom of the    cation form an aliphatic or aromatic ring with 4 to 8 C atoms which    is optionally substituted by one or more groups L,-   L is P¹-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)X, —C(═O)OR⁰⁰, —C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH,    —SF₅, optionally substituted silyl, aryl or heteroaryl with 1 to 12,    preferably 1 to 6 C atoms, and straight chain or branched alkyl,    alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   R⁰⁰ and R⁰⁰⁰ independently of each other denote H or alkyl with 1 to    12 C-atoms, and-   X is halogen, preferably F or Cl,

Preferred compounds of formula 1a-c are selected of formula 1a1-1c:

P¹—(CH₂)_(t)-[NR^(a)R^(b)R^(c)]⁺A⁻  1a1

P¹—(CH₂)_(t)—[PR^(a)R^(b)R^(c)]⁺A⁻  1b1

P¹—(CH₂)_(t)—[SR^(a)R^(b)R^(c)]⁺A⁻  1c1

wherein P¹, R^(a), R^(b), R^(c) and A⁻ are as defined in formula 1 and1a-1c, and t is an integer from 1 to 12.

P¹ is preferably an acrylate or methacrylate group. R^(a), R^(b) andR^(c) preferably denote straight-chain or branched alkyl with 1 to 12 Catoms, very preferably methyl or ethyl.

A⁻ is preferably an anion selected from the group of preferred or verypreferred anions as defined above.

R^(a), R^(b) and R^(c) preferably are selected from the group consistingof

-   -   a straight-chain or branched alkyl having 1-20 C atoms, which        optionally can be partially fluorinated, but not in α-position        to hetero-atom, and which can also include oxygen or/and sulfur        atoms in any positions in between carbon atoms,    -   saturated, partially or fully unsaturated cycloalkyl having 5-7        C atoms, which may be substituted by alkyl groups having 1-6 C        atoms.

Very preferably R^(a), R^(b) and R^(c) denote straight-chain or branchedalkyl having 4-20 C atoms, preferably 4-10 C atoms.

Preferred polymerisable cations P¹-Sp-C⁺ are selected from the groupconsisting of:

-   N-[2-(methacryloyloxy)ethyl]-N,N,N-trialkylammonium-   N-[2-(methacryloyloxy)ethyl]-N,N,N-trimethylammonium (MOTMA)-   N-[2-(methacryloyloxy)propyl]-N,N,N-trimethylammonium-   N-[2-(methacryloyloxy)ethyl]-N,N,N-trihexylammonium (MOTHA)-   N-[2-(methacryloyloxy)propyl]-N,N,N-trihexylammonium-   N-[(2-methacryloxy)-(AO)_(x)-A]-N,N,N-trialkylammonium-   1-[2-(methacryloyloxy)ethyl]-3-butylimidazolium-   1-(2-methacryloxyethyl)-3-methylimidazolium-   1-[(2-methacryloxy)-(AO)_(x)-A]-3-methylimidazolium-   1-[2-(methacryloyloxy)ethyl]-1-butylpyrrolidinium-   1-(2-methacryloxyethyl)-1-methylpyrrolidinium-   1-[(2-methacryloxy)-(AO)_(x)— A]-1-methylpyrrolidinium    wherein (AO)_(x) is a polyalkyl oxide preferably with x=1-10,    especially with x=2-4 and A especially=ethylene, propylene,-   1-[(2-methacryloxy)-C_(y)]-3-methylimidazolium,-   1-[(2-methacryloxy)-C_(y)]-1-methylpyrrolidinium,    wherein C_(y) is an alkyl chain preferably with y=1 to 12,    especially with y=1 to 4,-   N-(acryloxy-ethyl)-N,N,N-trimethyl ammonium (AOTMA),-   N-(acryloxy-ethyl)-N,N,N-trihexyl ammonium (AOTHA),-   N-(acryloxy-propyl)-N,N,N-trihexyl ammonium-   N-[3-(methacryloylamino)propyl]-N,N,N-trimethylammonium-   N-[3-(methacryloylamino)propyl]-N,N,N-trihexylammonium-   N,N,N,N-tetraallyl ammonium-   1-allyl-3-methylimidazolium-   1-allyl-1-methylpyrrolidinium-   N-butyl-4-vinyl-pyridinium-   N-ethyl-4-vinyl-pyridinium-   N-methyl-4-vinyl-pyridinium-   N-methyl-2-vinyl-pyridinium-   N,N-diallyl-N,N-dimethyl ammonium-   N-(vinylbenzyl)-N,N,N-trimethylammonium

Very preferred polymerisable cations include, without limitation,N-[2-(methacryloyloxy)ethyl]-N,N,N-trimethylammonium (MOTMA) andN-[2-(methacryloyloxy)ethyl]-N,N,N-trihexylammonium (MOTHA).

Suitable and preferred polymerisable ionic compounds include, withoutlimitation, the compounds listed in Table 1.

TABLE 1 Ref. Polymerisable Cation Anion MOTMA- TFPB

MOTHA- TFPB

MOTHA- FAP

[(C₂F₅)₃PF₃]⁻ MOTHA- NFS

[C₄F₉SO₃]⁻ MOTHA- NTF

[N(SO₂CF₃)₂]⁻ MOTHA- TCB

[B(CN)₄]⁻ MOTMA- AOT

MOTMA- NTF

[N(SO₂CF₃)₂]⁻ MOTMA- C

Cl⁻ MOTMA- MS

[CH₃SO₃]⁻

Especially preferred are polymerisable ionic compounds comprising ascation N-[2-(methacryloyloxy)ethyl]-N,N,N-trimethylammonium (MOTMA),N-[2-(methacryloyloxy)propyl]-N,N,N-trimethylammonium,N-[2-(acryloyloxy)ethyl]-N,N,N-trimethylammonium (AOTMA),N-[2-(methacryloyloxy)ethyl]-N,N,N-trihexylammonium (MOTHA),N-[2-(methacryloyloxy)propyl]-N,N,N-trihexylammonium orN-[2-(acryloyloxy)ethyl]-N,N,N-trihexylammonium (AOTHA) and as aniontetraphenylborate, tetrakis(3,5-bis(trifluoromethyl)phenyl)borate or(bis(2-2-ethyl hexyl) sulfosuccinate. Especially preferred are themethacrylate compounds.

The reactive organic compounds of the third preferred embodimentpreferably contain one or more polymerisable functional groups, and oneor more polar groups that increase the conductivity of the RMformulation.

They are preferably selected of formula 2

P¹-Sp³-G  2

wherein

-   P¹ is a polymerisable group,-   Sp³ is an alkylene spacer with 2 to 12 C atoms, which is optionally    substituted with one or more groups G, and wherein one or more CH₂    groups are optionally replaced by —O—, —S—, —CO—, NR⁰⁰R⁰⁰⁰, or    denotes a single bond, wherein R⁰⁰ and R⁰⁰⁰ independently of each    other denote H or alkyl with 1 to 12 C-atoms, and-   G is a polar group, preferably selected from COOH, OH, NH₂, NO₂,    SO₃H, SH, PO₃H₂, and benzene that is mono- or polysubstituted with    COOH, OH, NH₂, NO₂, SO₃H, SH or PO₃H₂.

P¹ is preferably an acrylate or methacrylate group. Sp is preferablyalkylene with 1 to 12 C atoms.

Preferred compounds of formula 2 are those of formula 2a and 2b:

wherein

-   P¹ is a polymerisable group,-   B¹ is H, R^(a), or

-   B² is H or R^(a),-   R^(a) is, on each occurrence identically or differently, OH, COOH,    NH₂, NO₂, SO₃H, SH, PO₃H₂,-   R^(b-f) are independently of each other H or R^(a), wherein at least    one of R^(b-f) denotes R^(a),-   a1 is an integer from 2 to 12,-   b1 is an integer from 0 to 12.

P¹ is preferably an acrylate or methacrylate group.

is preferably

wherein R^(a) and b1 are as defined in formula 2.

a1 is preferably 2, 3, 4, 5 or 6.

Preferred compounds of formula 2a and 2b are those of the followingformulae:

wherein P¹ and R^(a) are as defined in formula 2a, P¹ is preferably anacrylate or methacrylate group, R^(a) is preferably OH or COOH, and z isan integer from 2 to 12, preferably 2, 3, 4, 5 or 6.

Suitable and preferred compounds of formula 2a and 2b include, withoutlimitation, the following compounds:

wherein P¹ is as defined in formula 2a, and is preferably an acrylate ormethacrylate group.

Scheme 1 shows by way of example of MOTMA the synthesis of polymerisableionic compounds of the invention by ion exchange, which can be carriedout under conditions known to the person skilled in the art.

Equimolar ratios of polymerisable cations and salts comprising thedesired anion are reacted; for example Li NTF or K FAP or K NFS or K TCBwith MOTMA CI or MOTHA CI. The polymerisable ionic liquids can bepolymerised as show in Scheme 1.

The salts of NTF, FAP, NFS, TCB or MOTMA are commercially available orcan be synthesised by known methods, for example salts containingtetracyanoborate anions in accordance with the disclosure of WO2004/072089.

The synthesis of several polymerisable ionic liquids is known from theliterature. For example, the preparation of 1-allyl-3-methylimidazoliumbis(pentafluoroethyl)phosphinate from tris(pentafluoroethyl)phosphineoxide, N-methylimidazole, and allyl alcohol is described in WO2005/049555.

Fluoroalkylborate anions (FAB) and processes for their preparation aredescribed in EP 1205480 and EP 1229038.

The preparation of further compounds according to the invention can becarried out analogously to the illustrative reactions shown above. Thepreparation of further compounds according to the invention can also becarried out by other methods known per se to the person skilled in theart from the literature. In particular, other catalysts can be used.

The invention furthermore relates to the novel ionic organic compoundsor polymerisable ionic compounds as shown above and below.

Preferably the RM formulation comprises one or more polymerisablemesogenic compounds having only one polymerisable functional group(monoreactive), and one or more polymerisable mesogenic compounds havingtwo or more polymerisable functional groups (di- or multireactive).

The di- or multireactive RMs are preferably selected of formula I

P¹-Sp¹-MG-Sp²-P²  I

wherein P¹ and P² independently of each other denote a polymerisablegroup, Sp¹ and Sp² independently of each other are a spacer group or asingle bond, and MG is a rod-shaped mesogenic group, which is preferablyselected of formula II

-(A¹-Z¹)_(n)-A²-  II

wherein

-   A¹ and A² denote, in case of multiple occurrence independently of    one another, an aromatic or alicyclic group, which optionally    contains one or more heteroatoms selected from N, O and S, and is    optionally mono- or polysubstituted by L,-   L is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)X, —C(═O)OR⁰⁰, —C(═O)R⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅,    optionally substituted silyl, aryl or heteroaryl with 1 to 12,    preferably 1 to 6 C atoms, and straight chain or branched alkyl,    alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   R⁰⁰ and R⁰⁰⁰ independently of each other denote H or alkyl with 1 to    12 C-atoms,-   X is halogen, preferably F or Cl,-   Z¹ denotes, in case of multiple occurrence independently of one    another, —O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—,    —CO—NR⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰, —NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—,    —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—,    —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—,    —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a    single bond, preferably —COO—, —OCO— or a single bond,-   Y¹ and Y² independently of each other denote H, F, Cl or CN,-   n is 1, 2, 3 or 4, preferably 1 or 2, most preferably 2,-   n¹ is an integer from 1 to 10, preferably 1, 2, 3 or 4.

Preferred groups A¹ and A² include, without limitation, furan, pyrrol,thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene,cyclohexylene, bicyclooctylene, cyclohexenylene, pyridine, pyrimidine,pyrazine, azulene, indane, fluorene, naphthalene, tetrahydronaphthalene,anthracene, phenanthrene and dithienothiophene, all of which areunsubstituted or substituted by 1, 2, 3 or 4 groups L as defined above.

Particular preferred groups A¹ and A² are selected from 1,4-phenylene,pyridine-2,5-diyl, pyrimidine-2,5-diyl, thiophene-2,5-diyl,naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl,indane-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene wherein one or twonon-adjacent CH₂ groups are optionally replaced by O and/or S, whereinthese groups are unsubstituted or substituted by 1, 2, 3 or 4 groups Las defined above.

Preferred RMs of formula I are selected of formula Ia

wherein

-   P⁰ is, in case of multiple occurrence independently of one another,    a polymerisable group, preferably an acryl, methacryl, oxetane,    epoxy, vinyl, vinyloxy, propenyl ether or styrene group,-   Z⁰ is —COO—, —OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—, —C≡C—, —CH═CH—,    —OCO—CH═CH—, —CH═CH—COO—, or a single bond,-   L has the meanings given in formula I and is preferably, in case of    multiple occurrence independently of one another, selected from F,    Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C    atoms,-   r is 0, 1, 2, 3 or 4,-   x and y are independently of each other 0 or identical or different    integers from 1 to 12,-   z is 0 or 1, with z being 0 if the adjacent x or y is 0.

Very preferred RMs of formula I are selected from the followingformulae:

wherein P⁰, L, r, x, y and z are as defined in formula Ia.

Especially preferred are compounds of formula Ia1, Ia2 and Ia3, inparticular those of formula Ia1.

The concentration of di- or multireactive RMs, preferably those offormula I and its subformulae, in the RM formulation is preferably from30% to 99.9%, very preferably from 50 to 80%.

The monoreactive RMs are preferably selected from formula III:

P¹-Sp¹-MG-R  III

wherein P¹, Sp¹ and MG have the meanings given in formula I and II,

-   R denotes P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)X, —C(═O)OR⁰, —C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅,    optionally substituted silyl, straight chain or branched alkyl,    alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   X is halogen, preferably F or Cl, and-   R⁰⁰ and R⁰⁰⁰ are independently of each other H or alkyl with 1 to 12    C-atoms.

Preferably the RMs of formula II are selected from the followingformulae.

wherein P⁰, L, r, x, y and z are as defined in formula Ia,

-   R⁰ is alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,    alkylcarbonyloxy or alkoxycarbonyloxy with 1 or more, preferably 1    to 15 C atoms which is optionally fluorinated, or denotes Y⁰ or    P—(CH₂)_(y)—(O)_(z)—,-   X⁰ is —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR¹—, —NR⁰¹—CO—,    —NR⁰¹—CO—NR⁰¹—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—,    —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—,    —CH═CR⁰¹—, —CF═CF—, —C═C—, —CH≡CH—COO—, —OCO—CH═CH— or a single bond-   Y⁰ is F, Cl, CN, NO₂, OCH₃, OCN, SCN, SF₅, optionally fluorinated    alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy    with 1 to 4 C atoms, or mono-oligo- or polyfluorinated alkyl or    alkoxy with 1 to 4 C atoms,-   A⁰ is, in case of multiple occurrence independently of one another,    1,4-phenylene that is unsubstituted or substituted with 1, 2, 3 or 4    groups L, or trans-1,4-cyclohexylene,-   R^(01,02) are independently of each other H, R⁰ or Y⁰,-   u and v are independently of each other 0, 1 or 2,-   w is 0 or 1,    and wherein the benzene and napthalene rings can additionally be    substituted with one or more identical or different groups L.

Especially preferred are compounds of formula III1, III2, III3, III4,III5, III6, III7, III8, III9 and III10, in particular those of formulaIII1, III4, III6, III7 and III8.

The concentration of the monoreactive RMs in the RM formulation ispreferably from 1 to 90%, very preferably from 10 to 70%.

The polymer film according to the present invention is preferablyprepared by providing the RM formulation onto a substrate, aligning theRMs in the formulation into planar alignment (i.e. with the longmolecular axes of the RMs and LC molecules aligned parallel to thesubstrate), and polymerising the RM formulation in its LC phase at aselected temperature, for example by exposure to heat or actinicradiation, preferably by photopolymerisation, very preferably byUV-photopolymerisation, to fix the alignment of the LC molecules.

Polymerisation of the RM formulation is preferably carried out in thepresence of an initiator absorbing at the wavelength of the actinicradiation. For this purpose, preferably the RM formulation additionallycontains one or more polymerisation initiators.

For example, when polymerising by means of UV light, a photoinitiatorcan be used that decomposes under UV irradiation to produce freeradicals or ions that start the polymerisation reaction. Forpolymerising acrylate or methacrylate groups preferably a radicalphotoinitiator is used. For polymerising vinyl, epoxide or oxetanegroups preferably a cationic photoinitiator is used. It is also possibleto use a thermal polymerisation initiator that decomposes when heated toproduce free radicals or ions that start the polymerisation. Typicalradical photoinitiators are for example the commercially availableIrgacure® or Darocure® (Ciba AG). for example Irgacure 651, Irgacure 907or Irgacure 369. A typical cationic photoinitiator is for example UVI6974 (Union Carbide).

The concentration of the polymerisation initiator in the RM formulationis preferably from 0.01 to 5%, very preferably from 0.1 to 3.

In another preferred embodiment of the present invention the RMformulation additionally contains one or more surfactants. Thesurfactants are selected such that they to promote planar surfacealignment of the LC molecules when preparing the polymer film. Suitablesurfactants are described for example in J. Cognard, Mol. Cryst. Liq.Cryst., Supplement 1, 1-77 (1981).

Especially preferred are non-ionic surfactants, preferably polymerisableor unpolymerisable fluorocarbon surfactants, like for example Fluorad®FC-171 (from 3M Co.) or Zonyl FSN® (from DuPont), or Fluorad® FX-13 orFX-14 (from 3M Co.).

The concentration of the surfactants in the RM formulation is preferablyfrom 0.1 to 5%, very preferably from 0.1 to 1%.

Preferably the RM formulation comprises:

-   -   30 to 99.9% of polymerisable mesogenic compounds having two or        more polymerisable functional groups,    -   0 to 90% polymerisable mesogenic compounds having only one

polymerisable functional group,

-   -   0.01 to 5% of one or more conductive additives,    -   0 to 5% of one or more surfactants,    -   0 to 5% of one or more polymerisation initiators.

Very preferably the RM formulation invention comprises:

-   -   50 to 80% of polymerisable mesogenic compounds having two or        more polymerisable functional groups,    -   10 to 70% polymerisable mesogenic compounds having only one        polymerisable functional group,    -   0.1 to 1% of one or more conductive additives,    -   0.1 to 1% of one or more surfactants,    -   0.1 to 3% of one or more polymerisation initiators.

The RM formulation may also comprise one or more monoreactivepolymerisable non-mesogenic compounds, preferably in an amount of 0 to30%, very preferably 0 to 15%. Typical examples are alkylacrylates oralkylmethacrylates.

The RM formulation may also comprise one or more di- or multireactivepolymerisable non-mesogenic compounds, preferably in an amount of 0 to30%, very preferably 0 to 15%, alternatively or in addition to the di-or multireactive polymerisable mesogenic compounds. Typical examples ofdireactive non-mesogenic compounds are alkyldiacrylates oralkyldimethacrylates with alkyl groups of 1 to 20 C atoms. Typicalexamples of multireactive non-mesogenic compounds aretrimethylpropanetrimethacrylate or pentaerythritoltetraacrylate.

The RM formulation may also comprise a polymeric binder or one or moremonomers capable of forming a polymeric binder, and/or one or moredispersion auxiliaries. Suitable binders and dispersion auxiliaries aredisclosed for example in WO 96/02597. Preferably, however, the RMformulation does not contain a binder or dispersion auxiliary.

The RM formulation can additionally comprise one or more additives likefor example catalysts, sensitizers, stabilizers, inhibitors,chain-transfer agents, co-reacting monomers, surface-active compounds,lubricating agents, wetting agents, dispersing agents, hydrophobingagents, adhesive agents, flow improvers, degassing or defoaming agents,deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes,pigments or nanoparticles.

The RM formulation preferably exhibits a nematic LC phase, verypreferably a nematic at room temperature, or a smectic phase and anematic phase.

Preferably the RM formulation further comprises one or more organicsolvents. The solvents are preferably selected from ketones such asacetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutylketone or cyclohexanone; acetates such as methyl, ethyl or butyl acetateor methyl acetoacetate; alcohols such as methanol, ethanol or isopropylalcohol; aromatic solvents such as toluene or xylene; alicyclichydrocarbons such as cyclopentane or cyclohexane; halogenatedhydrocarbons such as di- or trichloromethane; glycols or their esterssuch as PGMEA (propyl glycol monomethyl ether acetate), γ-butyrolactone.

It is also possible to use binary, ternary or higher mixtures of theabove solvents.

In case the RM formulation contains one or more solvents, the totalconcentration of all solids, including the RMs, in the solvent(s) ispreferably from 10 to 60%.

In formulae 1, 2, I, II, III and their preferred subformulae, L ispreferably selected from F, Cl, CN, NO₂ or straight chain or branchedalkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonlyoxy oralkoxycarbonyloxy with 1 to 12 C atoms, wherein the alkyl groups areoptionally perfluorinated, or P-Sp-.

Very preferably L is selected from F, Cl, CN, NO₂, CH₃, C₂Hs, C(CH₃)₃,CH(CH₃)₂, CH₂CH(CH₃)C₂H₅, OCH₃, OC₂Hs, COCH₃, COC₂H₅, COOCH₃, COOC₂H₅,CF₃, OCF₃, OCHF₂, OC₂F₅ or P-Sp-, in particular F, Cl, CN, CH₃, C₂Hs,C(CH₃)₃, CH(CH₃)₂, OCH₃, COCH₃ or OCF₃, most preferably F, Cl, CH₃,C(CH₃)₃, OCH₃ or COCH₃, or P-Sp-.

A substituted benzene ring of the formula

is preferably

with L having each independently one of the meanings given above.

In formulae 1, 2, I, II, III and their preferred subformulae, an alkylor alkoxy radical, i.e. where the terminal CH₂ group is replaced by —O—,can be straight-chain or branched. It is preferably straight-chain, has2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordingly is preferably ethyl,propyl, butyl, pentyl, hexyl, heptyl, octyl, ethoxy, propoxy, butoxy,pentoxy, hexoxy, heptoxy, or octoxy, furthermore methyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, nonoxy, decoxy,undecoxy, dodecoxy, tridecoxy or tetradecoxy, for example.

Oxaalkyl, i.e. where one CH₂ group is replaced by —O—, is preferablystraight-chain 2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or3-oxabutyl (=2-methoxyethyl), 2-, 3-, or 4-oxapentyl, 2-, 3-, 4-, or5-oxahexyl, 2-, 3-, 4-, 5-, or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-,7-, 8- or 9-oxadecyl, for example.

An alkyl group wherein one or more CH₂ groups are replaced by —CH═CH—can be straight-chain or branched. It is preferably straight-chain, has2 to 10 C atoms and accordingly is preferably vinyl, prop-1-, orprop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl,hex-1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- orhept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-,4-, 5-, 6-, 7- or non-8-enyl, dec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- ordec-9-enyl.

Especially preferred alkenyl groups are C₂-C₇-1E-alkenyl,C₄-C₇-3E-alkenyl, C₅-C₇-4-alkenyl, C₆-C₇-5-alkenyl and C₇-6-alkenyl, inparticular C₂-C₇-1E-alkenyl, C₄-C₇-3E-alkenyl and C5-C₇-4-alkenyl.Examples for particularly preferred alkenyl groups are vinyl,1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl,3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl,4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groupshaving up to 5 C atoms are generally preferred.

In an alkyl group wherein one CH₂ group is replaced by —O— and one by—CO—, these radicals are preferably neighboured. Accordingly theseradicals together form a carbonyloxy group —CO—O— or an oxycarbonylgroup —O—CO—. Preferably this group is straight-chain and has 2 to 6 Catoms. It is accordingly preferably acetyloxy, propionyloxy, butyryloxy,pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl,butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl,2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl,3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl,ethoxy-carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl,2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl,2-(propoxy-carbonyl)ethyl, 3-(methoxycarbonyl)propyl,3-(ethoxycarbonyl)propyl, 4-(methoxycarbonyl)-butyl.

An alkyl group wherein two or more CH₂ groups are replaced by —O— and/or—COO— can be straight-chain or branched. It is preferably straight-chainand has 3 to 12 C atoms. Accordingly it is preferablybis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl,4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxy-hexyl,7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl,10,10-bis-carboxy-decyl, bis-(methoxycarbonyl)-methyl,2,2-bis-(methoxycarbonyl)-ethyl, 3,3-bis-(methoxycarbonyl)-propyl,4,4-bis-(methoxycarbonyl)-butyl, 5,5-bis-(methoxycarbonyl)-pentyl,6,6-bis-(methoxycarbonyl)-hexyl, 7,7-bis-(methoxycarbonyl)-heptyl,8,8-bis-(methoxycarbonyl)-octyl, bis-(ethoxycarbonyl)-methyl,2,2-bis-(ethoxycarbonyl)-ethyl, 3,3-bis-(ethoxycarbonyl)-propyl,4,4-bis-(ethoxycarbonyl)-butyl, 5,5-bis-(ethoxycarbonyl)-hexyl.

An alkyl or alkenyl group that is monosubstituted by CN or CF₃ ispreferably straight-chain. The substitution by CN or CF₃ can be in anydesired position.

An alkyl or alkenyl group that is at least monosubstituted by halogen ispreferably straight-chain. Halogen is preferably F or Cl, in case ofmultiple substitution preferably F. The resulting groups include alsoperfluorinated groups. In case of monosubstitution the F or Clsubstituent can be in any desired position, but is preferably inω-position. Examples for especially preferred straight-chain groups witha terminal F substituent are fluoromethyl, 2-fluoroethyl,3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and7-fluoroheptyl. Other positions of F are, however, not excluded.

R⁰⁰ and R⁰⁰⁰ are preferably selected from H, straight-chain or branchedalkyl with 1 to 12 C atoms.

—CY¹═CY²— is preferably —CH═CH—, —CF═CF— or —CH═C(CN)—.

Halogen is F, Cl, Br or I, preferably F or Cl.

R, R⁰, R¹ and R² can be an achiral or a chiral group. Particularlypreferred chiral groups are 2-butyl (=1-methylpropyl), 2-methylbutyl,2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, inparticular 2-methylbutyl, 2-methylbutoxy, 2-methylpentoxy,3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2-octyloxy,2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-hexyl,2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxyoctoxy, 6-methyloctoxy,6-methyloctanoyloxy, 5-methylheptyloxycarbonyl, 2-methylbutyryloxy,3-methylvaleroyloxy, 4-methylhexanoyloxy, 2-chlorpropionyloxy,2-chloro-3-methylbutyryloxy, 2-chloro-4-methylvaleryloxy,2-chloro-3-methylvaleryloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl,1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy,1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy,1,1,1-trifluoro-2-octyloxy, 1,1,1-trifluoro-2-octyl,2-fluoromethyloctyloxy for example. Very preferred are 2-hexyl, 2-octyl,2-octyloxy, 1,1,1-trifluoro-2-hexyl, 1,1,1-trifluoro-2-octyl and1,1,1-trifluoro-2-octyloxy.

Preferred achiral branched groups are isopropyl, isobutyl(=methylpropyl), isopentyl (=3-methylbutyl), isopropoxy,2-methyl-propoxy and 3-methylbutoxy.

In formulae 1, 2, I, II, III and their preferred subformulae, thepolymerisable groups P¹, P² and P⁰ denote a group that is capable ofparticipating in a polymerisation reaction, like radical or ionic chainpolymerisation, polyaddition or polycondensation, or capable of beinggrafted, for example by condensation or addition, to a polymer backbonein a polymer analogous reaction. Especially preferred are polymerisablegroups for chain polymerisation reactions, like radical, cationic oranionic polymerisation. Very preferred are polymerisable groupscomprising a C—C double or triple bond, and polymerisable groups capableof polymerisation by a ring-opening reaction, like oxetanes or epoxides.

Suitable and preferred polymerisable groups P¹, P² and P⁰ include,without limitation, CH₂═CW¹—COO—, CH₂═CW¹—CO—,

CH₂═CW²—(O)_(k1)—, CH₃—CH═CH—O—, (CH₂═CH)₂CH—OCO—, (CH₂═CH—CH₂)₂CH—OCO—,(CH₂═CH)₂CH—O—, (CH₂═CH—CH₂)₂N—, (CH₂═CH—CH₂)₂N—CO—, HO—CW²W³—,HS—CW²W³—, HW²N—, HO—CW²W³—NH—, CH₂═CW¹—CO—NH—,CH₂═CH—(COO)_(k1)-Phe-(O)_(k2)—, CH₂═CH—(CO)_(k1)-Phe-(O)_(k2)—,Phe-CH═CH—, HOOC—, OCN—, and W⁴W⁵W⁶Si—, with W¹ being H, F, Cl, CN, CF₃,phenyl or alkyl with 1 to 5 C-atoms, in particular H, C₁ or CH₃, W² andW³ being independently of each other H or alkyl with 1 to 5 C-atoms, inparticular H, methyl, ethyl or n-propyl, W⁴, W⁵ and W⁶ beingindependently of each other Cl, oxaalkyl or oxacarbonylalkyl with 1 to 5C-atoms, W⁷ and W⁸ being independently of each other H, Cl or alkyl with1 to 5 C-atoms, Phe being 1,4-phenylene that is optionally substituted,preferably by one or more groups L as defined above (except for themeaning P-Sp-), and k₁ and k₂ being independently of each other 0 or 1.

Very preferred polymerisable groups P¹, P² and P⁰ are selected fromCH₂═CW¹—COO—, CH₂═CW¹—CO—,

(CH₂═CH)₂CH—OCO—, (CH₂═CH—CH₂)₂CH—OCO—, (CH₂═CH)₂CH—O—, (CH₂═CH—CH₂)₂N—,(CH₂═CH—CH₂)₂N—CO—, HO—CW²W³—, HS—CW²W³—, HW²N—, HO—CW²W³—NH—,CH₂═CW¹—CO—NH—, CH₂═CH—(COO)_(k1)-Phe-(O)_(k2)—,CH₂═CH—(CO)_(k1)-Phe-(O)_(k2)—, Phe-CH═CH—, HOOC—, OCN—, and W⁴W⁵W⁶Si—,with W¹ being H, F, Cl, CN, CF₃, phenyl or alkyl with 1 to 5 C-atoms, inparticular H, F, C₁ or CH₃, W² and W³ being independently of each otherH or alkyl with 1 to 5 C-atoms, in particular H, methyl, ethyl orn-propyl, W⁴, W⁵ and W⁶ being independently of each other Cl, oxaalkylor oxacarbonylalkyl with 1 to 5 C-atoms, W⁷ and W⁸ being independentlyof each other H, Cl or alkyl with 1 to 5 C-atoms, Phe being1,4-phenylene that is optionally substituted preferably by one or moregroups L as defined above (except for the meaning P-Sp-), and k₁ and k₂being independently of each other 0 or 1.

Most preferred polymerisable groups P¹, P² and P⁰ are selected fromCH₂═CH—COO—, CH₂═C(CH₃)—COO—, CH₂═CF—COO—, (CH₂═CH)₂CH—OCO—,(CH₂═CH)₂CH—O—,

Polymerisation can be carried out according to methods that are known tothe ordinary expert and described in the literature, for example in D.J. Broer; G. Challa; G. N. Mol, Macromol. Chem., 1991, 192, 59.

In formulae 1, 2, I, II, III and their preferred subformulae, the spacergroups Sp, Sp¹ and Sp² are preferably selected of formula Sp′-X′, suchthat e.g. P-Sp- is P-Sp′-X′—, wherein

-   Sp′ is alkylene with 1 to 20 C atoms, preferably 1 to 12 C-atoms,    which is optionally mono- or polysubstituted by F, Cl, Br, I or CN,    and wherein one or more non-adjacent CH₂ groups are optionally    replaced, in each case independently from one another, by —O—, —S—,    —NH—, —NR⁰—, —SiR⁰R⁰⁰—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—,    —NR⁰—CO—O—, —O—CO—NR⁰—, —NR⁰—CO—NR⁰—, —CH═CH— or —C≡C— in such a    manner that O and/or S atoms are not linked directly to one another,-   X′ is —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR—, —NR⁰—CO—,    —NR⁰—CO—NR⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—,    —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—,    —CH═CR⁰—, —CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single    bond,-   R⁰ and R⁰⁰ are independently of each other H or alkyl with 1 to 12    C-atoms, and-   Y¹ and Y² are independently of each other H, F, Cl or CN.

X′ is preferably —O—, —S—CO—, —COO—, —OCO—, —O—COO—, —CO—NR⁰—, —NR⁰—CO—,—NR⁰—CO—NR⁰— or a single bond.

Typical groups Sp′ are, for example, —(CH₂)_(p1)—,—(CH₂CH₂O)_(q1)—CH₂CH₂—, —CH₂CH₂—S—CH₂CH₂— or —CH₂CH₂—NH—CH₂CH₂— or—(SiR⁰R⁰⁰—O)_(p1)—, with p1 being an integer from 2 to 12, q1 being aninteger from 1 to 3 and R⁰ and R⁰⁰ having the meanings given above.

Preferred groups Sp′ are ethylene, propylene, butylene, pentylene,hexylene, heptylene, octylene, nonylene, decylene, undecylene,dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxy-butylene,ethylene-thioethylene, ethylene-N-methyl-iminoethylene,1-methylalkylene, ethenylene, propenylene and butenylene for example.

Further preferred are compounds wherein the polymerisable group isdirectly attached to the mesogenic group without a spacer group Sp.

In case of compounds with two or more groups P¹-Sp¹- etc., thepolymerisable groups P¹ and the spacer groups Sp¹ can be identical ordifferent.

In another preferred embodiment the reactive compounds comprise one ormore terminal groups R^(0,1,2) or substituents L that are substituted bytwo or more polymerisable groups P or P-Sp- (multifunctionalpolymerisable groups). Suitable multifunctional polymerisable groups ofthis type are disclosed for example in U.S. Pat. No. 7,060,200 B1 oderUS 2006/0172090 A1. Very preferred are compounds comprising one or moremultifunctional polymerisable groups selected from the followingformulae:

—X-alkyl-CHP¹—CH₂—CH₂P²  P1

—X′-alkyl-C(CH₂P¹)(CH₂P²)—CH₂P³  P2

—X′-alkyl-CHP¹CHP²—CH₂P₃  P3

—X′-alkyl-C(CH₂P¹)(CH₂P²)—C_(aa)H_(2aa+1)  P4

—X′-alkyl-CHP¹—CH₂P²  P5

—X′-alkyl-CHP¹P²  P5

—X′-alkyl-CP¹P²—C_(aa)H_(2aa+1)  P6

—X′-alkyl-C(CH₂P¹)(CH₂P²)—CH₂OCH₂—C(CH₂P³)(CH₂P⁴)CH₂P⁵  P7

—X′-alkyl-CH((CH₂)_(aa)P¹)((CH₂)_(bb)P²)  P8

—X′-alkyl-CHP¹CHP²—C_(aa)H_(2aa+1)  P9

wherein

-   alkyl is straight-chain or branched alkylene having 1 to 12 C-atoms    which is unsubstituted, mono- or polysubstituted by F, Cl, Br, I or    CN, and wherein one or more non-adjacent CH₂ groups are optionally    replaced, in each case independently from one another, by —O—, —S—,    —NH—, —NR⁰—, —SiR⁰R⁰⁰—, —CO—, —COO—, —OCO—, —O—CO—O—, —S—CO—,    —CO—S—, —SO₂—, —CO—NR⁰—, —NR⁰—CO—, —NR⁰—CO—NR⁰⁰—, —CY¹═CY²— or —C≡C—    in such a manner that O and/or S atoms are not linked directly to    one another, with R⁰ and R⁰⁰ having the meanings given above, or    denotes a single bond,-   aa and bb are independently of each other 0, 1, 2, 3, 4, 5 or 6,-   X′ is as defined above, and-   P¹⁻⁵ independently of each other have one of the meanings given for    P above.

The preparation of polymer films according to this invention can becarried out by methods that are known to the skilled person anddescribed in the literature, for example in D. J. Broer; G. Challa; G.N. Mol, Macromol. Chem., 1991, 192, 59. Typically the RM formulation iscoated or otherwise applied onto a substrate where it aligns intouniform orientation, preferably planar alignment (i.e. with the longmolecular axes of the calamitic RMs or LC molecules aligned parallel tothe substrate), and polymerised in situ in its LC phase at a selectedtemperature for example by exposure to heat or actinic radiation,preferably by photo-polymerisation, very preferably byUV-photopolymerisation, to fix the alignment of the LC molecules. Ifnecessary, uniform alignment can promoted by additional means likeshearing or annealing the LC material, surface treatment of thesubstrate, or adding surfactants to the LC material.

As substrate for example glass or quartz sheets or plastic films can beused. It is also possible to put a second substrate on top of the coatedmaterial prior to and/or during and/or after polymerisation. Thesubstrates can be removed after polymerisation or not. When using twosubstrates in case of curing by actinic radiation, at least onesubstrate has to be transmissive for the actinic radiation used for thepolymerisation. Isotropic or birefringent substrates can be used. Incase the substrate is not removed from the polymerised film afterpolymerisation, preferably isotropic substrates are used.

Suitable and preferred plastic substrates are for example films ofpolyester such as polyethyleneterephthalate (PET) orpolyethylene-naphthalate (PEN), polyvinylalcohol (PVA), polycarbonate(PC) or triacetylcellulose (TAC), very preferably PET or TAC films. Asbirefringent substrates for example uniaxially stretched plastics filmcan be used. PET films are commercially available for example fromDuPont Teijin Films under the trade name Melinex®.

Preferably the RMs and the other solid additives are dissolved in asolvent. The solution is then coated or printed onto the substrate, forexample by spin-coating or printing or other known techniques, and thesolvent is evaporated off before polymerisation. In many cases it issuitable to heat the coated solution in order to facilitate theevaporation of the solvent.

The RM formulaion can be applied onto the substrate by conventionalcoating techniques like spin-coating or blade coating. It can also beapplied to the substrate by conventional printing techniques which areknown to the expert, like for example screen printing, offset printing,reel-to-reel printing, letter press printing, gravure printing,rotogravure printing, flexographic printing, intaglio printing, padprinting, heat-seal printing, inkjet printing or printing by means of astamp or printing plate.

The RM formulation should preferably exhibit planar alignment. This canbe achieved for example by rubbing treatment of the substrate, byshearing the material during or after coating, by annealing the materialbefore polymerisation, by application of an alignment layer, by applyinga magnetic or electric field to the coated material, or by the additionof surface-active compounds to the formulation. Reviews of alignmenttechniques are given for example by I. Sage in “Thermotropic LiquidCrystals”, edited by G. W. Gray, John Wiley & Sons, 1987, pages 75-77;and by T. Uchida and H. Seki in “Liquid Crystals—Applications and UsesVol. 3”, edited by B. Bahadur, World Scientific Publishing, Singapore1992, pages 1-63. A review of alignment materials and techniques isgiven by J. Cognard, Mol. Cryst. Liq. Cryst. 78, Supplement 1 (1981),pages 1-77.

It is also possible to apply an alignment layer onto the substrate andprovide the RM formulation onto this alignment layer. Suitable alignmentlayers are known in the art, like for example rubbed polyimide oralignment layers prepared by photoalignment as described in U.S. Pat.No. 5,602,661, U.S. Pat. No. 5,389,698 or U.S. Pat. No. 6,717,644.

It is also possible to induce or improve alignment by annealing the RMformulation at elevated temperature, but below its clearing temperature,prior to polymerisation.

Polymerisation is achieved for example by exposing the polymerisablematerial to heat or actinic radiation. Actinic radiation meansirradiation with light, like UV light, IR light or visible light,irradiation with X-rays or gamma rays or irradiation with high energyparticles, such as ions or electrons. Preferably polymerisation iscarried out by UV irradiation. As a source for actinic radiation forexample a single UV lamp or a set of UV lamps can be used. When using ahigh lamp power the curing time can be reduced. Another possible sourcefor actinic radiation is a laser, like for example a UV, IR or visiblelaser.

The curing time depends, inter alia, on the reactivity of the RMformulation, the thickness of the coated layer, the type ofpolymerisation initiator and the power of the UV lamp. The curing timeis preferably ≦5 minutes, very preferably ≦3 minutes, most preferably ≦1minute. For mass production short curing times of ≦30 seconds arepreferred.

The polymerisation process is not limited to one curing step. It is alsopossible to carry out polymerisation by two or more steps, in which thefilm is exposed to two or more lamps of the same type, or two or moredifferent lamps in sequence. The curing temperature of different curingsteps might be the same or different. The lamp power and dose fromdifferent lamps might also be the same or different. In addition to theconditions described above, the process steps may also include a heatstep between exposure to different lamps, as described for example in JP2005-345982 A and JP 2005-265896 A.

Preferably polymerisation is carried out in air, but polymerising in aninert gas atmosphere like nitrogen or argon is also possible.

The thickness of a polymer film according to the present invention ispreferably from 0.2 to 10 microns, very preferably from 0.3 to 5microns, most preferably from 0.5 to 3 microns.

The polymer films and materials of the present invention can be used inoptical, electrooptical or electronic devices ort components thereof.For example, they can be used in optical retardation films, polarizers,compensators, beam splitters, reflective films, alignment layers, colourfilters, antistatic protection sheets, or electromagnetic interferenceprotection sheets, polarization controlled lenses for autostereoscopic3D displays, and IR reflection films for window applications.

The polymer films, materials and components can be used in devices isselected from electrooptical displays, especially liquid crystaldisplays (LCDs), autostereoscopic 3D displays, organic light emittingdiodes (OLEDs), optical data storage devices, and window applications.

The polymer films and materials of the present invention can be usedoutside the switchable LC cell of an LCD or between the substrates,usually glass substrates, forming the switchable LC cell and containingthe switchable LC medium (incell application).

The polymer film and materials of the present invention can be used inconventional LC displays, for example displays with vertical alignmentlike the DAP (deformation of aligned phases), ECB (electricallycontrolled birefringence), CSH (colour super homeotropic), VA(vertically aligned), VAN or VAC (vertically aligned nematic orcholesteric), MVA (multi-domain vertically aligned), PVA (patternedvertically aligned) or PSVA (polymer stabilised vertically aligned)mode; displays with bend or hybrid alignment like the OCB (opticallycompensated bend cell or optically compensated birefringence), R—OCB(reflective OCB), HAN (hybrid aligned nematic) or pi-cell (π-cell) mode;displays with twisted alignment like the TN (twisted nematic), HTN(highly twisted nematic), STN (super twisted nematic), AMD-TN (activematrix driven TN) mode; displays of the IPS (in plane switching) mode,or displays with switching in an optically isotropic phase.

The polymer films of the present invention can be used for various typesof optical films, like twisted optical retarders, reflective polarisersand brightness enhancement films.

The invention also relates to an RM formulation as described above andbelow, which has increased electrical conductivity and decreasedelectrical resistivity, preferably a resistivity ≦1E06 Ω·m, verypreferably ≦7E05 Ω·m and a conductivity ≧1E-06 S/m, very preferably≧1.2E68 S/m.

The invention also relates to a polymer film with reduced (electrical)sheet resistance, which comprises or consists of a polymerised RMformulation as described above and below, or is obtained by polymerisinga layer of an RM formulation as described above and below, preferablywherein the RMs are aligned, and preferably at a temperature where theRM formulation exhibits a liquid crystal phase.

One preferred embodiment relates to polymer films having a sheetresistance <10,000 Ω/sq. Such films are especially suitable for exampleas antistatic protection sheets. Another preferred embodiment relates topolymer films having a sheet resistance <50 Ω/sq, very preferably <5Ω/sq. Such films are suitable for example as electromagneticinterference protection sheets. The sheet resistance can be measured bythe four point probe method or Van der Pauw method, which is describedin the literature.

The thickness of a polymer film with reduced sheet resistance, includingthe above mentioned preferred embodiments, is preferably from 0.2 to 5,very preferably from 0.5 to 3 microns.

Above and below, percentages are percent by weight unless statedotherwise. All temperatures are given in degrees Celsius. m.p. denotesmelting point, cl.p. denotes clearing point, T_(g) denotes glasstransition temperature. Furthermore, C=crystalline state, N=nematicphase, S=smectic phase and I=isotropic phase. The data between thesesymbols represent the transition temperatures. An denotes the opticalanisotropy or birefringence (Δn=n_(e)−n_(o), where n_(o) denotes therefractive index parallel to the longitudinal molecular axes and n_(e)denotes the refractive index perpendicular thereto), measured at 589 nmand 20° C. The optical and electrooptical data are measured at 20° C.,unless expressly stated otherwise. “Clearing point” and “clearingtemperature” mean the temperature of the transition from an LC phaseinto the isotropic phase.

Unless stated otherwise, the percentages of components of apolymerisable formulation as given above and below refer to the totalamount of solids in the formulation without any solvents.

Unless stated otherwise, all optical, electrooptical properties andphysical parameters like birefringence, permittivity, electricalconductivity, electrical resistivity and sheet resistance, refer to atemperature of 20° C.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Each feature disclosed in this specification, unless statedotherwise, may be replaced by alternative features serving the same,equivalent or similar purpose. Thus, unless stated otherwise, eachfeature disclosed is one example only of a generic series of equivalentor similar features.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

The following examples are intended to explain the invention withoutrestricting it. The methods, structures and properties describedhereinafter can also be applied or transferred to materials that areclaimed in this invention but not explicitly described in the foregoingspecification or in the examples.

Example 1

The RM formulation RMS1 is prepared as follows:

Compound Concentration (wt. %) Methyl isobutyl ketone (MIBK) 70.000%Compound (1)  7.083% Compound (2)  7.083% Compound (3) 11.346% Compound(4)  2.799% Fluorad FC171 ®  0.150% Irgacure 907 ®  1.515% Irganox1076 ®  0.024%

The following conductive additives are used:

No. CAS-No. Name Structure CA1 MOTMA- NTF

CA2 5039-78-1 MOTMA- C

CA3 6891-44-7 MOTMA- MS

CA4 H₂O CA5 Isopropyl- alcolhol CA6 Formula 2a1a

MOTMA-C and MOTMA-MS are available from Sigma-Aldrich. MOTMA-NTF waspreared as described in Scheme 1 above.

The conductive additives are to the RM formulation either alone or incombination with each other, for example, by combining additive CA2 withadditive CA4, or combining additive CA3 with additive CA4.

Conductivity Measurements

The effect of solvent type and additive concentration are investigatedby measuring the electrical resistivity and conductivity, using a 1Vapplied voltage. The results are shown in Table 1 below.

TABLE 1 Resistivity/ Conductivity/ Sample RH % Ohm * cm S * cm⁻¹ Toluene20 1.76E+13 5.70E−14 PGMEA 19 2.22E+08 4.50E−09 Methyl ethyl ketone 191.64E+08 6.10E−09 (MEK) Methyl isobutyl ketone 19 1.02E+08 9.85E−09(MIBK) RMS1 19 8.83E+07 1.13E−08 RMS1 + 0.3% CA1 19 6.34E+07 1.58E−08RMS1 + 1% CA1 19 4.54E+07 2.20E−08 RMS1 + 1% CA4 19 5.23E+07 1.91E−08

It can be seen that there is a significant variation of the resistivityand conductivity depending on the solvent type. The above RM formulationRMS1 (reactive mesogen mixture in MIBK, with 30% solids) has a higherconductivity than the pure base solvent MIBK. The addition of a smallamount of water (CA4) or conductive additive CA1 (0.3-1% MOTA-NTF inthis example) results in a significant increase in conductivity.

Example 2 Effect on RM Processing—Additive CA1

Additive CA1 is added in concentrations of 0.1, 0.5 and 1% to theformulation RMS1. The individual formulations with and without additiveCA1 are coated on rubbed polyimide glass by spin coating (3000 rpm, 30sec). This is followed by an annealing step (at 50° C. for 60 sec) toremove the solvent. The coatings are cooled to room temperature and thenexposed to UV light from a high pressure mercury lamp (1200 mJ/cm²),forming a polymerised film.

Optical properties of the film are measured by ellipsometry, with arotating sample stage providing retardation values at angles ofincidence from −40 to 40 degrees. The results are shown in FIG. 1 forthe films prepared from RMS1 containing 0%, 0.1%, 0.5% and 1% of CA1. Noeffect of the additive on the optical properties of the films isobserved. All films show the same retardation value and off-axisperformance for each concentration of CA1.

Example 3 Effect on RM Processing—Additive CA2

Polymerised RM films are prepared from RMS 1 without and with varyingconcentrations of additive CA2 as described above in Example 2, andtheir retardation values are measured by ellipsometry. The results areshown in FIG. 2. No effect of the additive on the processing or opticalproperties of the film is observed.

Example 4 Effect on Film Durability—Additive CA1, CA2, CA3

To investigate a possible effect of the additive on the film durability,RM film samples are prepared from RMS 1 without or with additive CA1,CA2 or CA3 in concentrations of 0.1%, 0.5% and 1%, respectively, by themethod as described above. The film samples are then placed in atemperature chamber at 120° C. and their retardation is measuredperiodically by ellipsometry. The effect of the temperature treatment onthe retardation of the films is shown in FIGS. 3, 4 and 5 for additiveCA1, CA2 and CA3, respectively. It can be seen that the retardation dropdue to exposure to high temperature is identical, within experimentalerror, for film samples with concentrations of the additive between0-1%. The same trend was observed for each of additive CA1, CA2 and CA3.

1. A formulation comprising >50% of one or more polymerisable mesogeniccompounds, and one or more conductive additives.
 2. A formulationaccording to claim 1, characterized in that the conductive additives areselected from ionic organic compounds.
 3. A formulation according toclaim 2, characterized in that the conductive additives contain anorganic cation selected from the group consisting of ammonium,phosphonium, sulfonium, uronium, thiouronium, guanidinium andheterocyclic cations.
 4. A formulation according to claim 3,characterized in that the conductive additives contain an organic cationselected from the group consisting of tetraalkylammonium,tetraalkylphosphonium, N-alkylpyridinium, N,N-dialkylpyrrolidinium,1,3-dialkylimidazolium or trialkylsulfonium cation.
 5. A formulationaccording to claim 2, characterized in that the conductive additivescontain an anion selected from the group consisting of halide, borate,imide, phosphate, sulfonate, sulfate, succinate, naphthenate andcarboxylate.
 6. A formulation according to claim 5, characterized inthat the conductive additives contain an anion selected from the groupconsisting of chloride, bromide, iodide, tetrafluoroborate,tetracyanoborate (TCB), difluoro-dicyano borate, fluoro-tricyano borate,perfluoroalkyl-fluoro-dicyano borate, pentafluoroethyl-fluoro-dicyanoborate, perfluoroalkyl-difluoro-cyano borate,pentafluoroethyl-difluoro-cyano borate, perfluoroalkyl-fluoro borate(FAB), perfluoroalkyl-alkoxy-dicyano borate, alkoxy-tricyano borate,methoxy-tricyano borate, ethoxy-tricyano borate,2,2,2-trifluoroethoxy-tricyano borate,bis(2,2,2-trifluoroethoxy)-dicyano borate, tetraphenylborate (TPB),tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (TFPB),tetrakis(4-chlorophenyl)borate, tetrakis(4-fluorophenyl)borate,tetrakis(pentafluorophenyl)borate,tetrakis(2,2,2-trifluoroethoxy)borate, bis(oxalato)borate,bis(trifluoromethylsulfonyl)imide (NTF), bis(fluorosulfonyl)imide,bis[bis(pentafluoroethyl)phosphinyl]imide (FPI),tris(trifluoromethylsulfonyl)methide, (fluoroalkyl)fluorophosphates,tris(pentafluoroethyl)trifluorophosphate (FAP),bis(pentafluoroethyl)tetrafluorophosphate,(pentafluoroethyl)pentafluorophosphate,tris(nonafluorobutyl)trifluorophosphate,bis(nonafluorobutyl)tetrafluorophosphate,(nonafluorobutyl)pentafluorophosphate, hexafluorophosphate,bis(fluoroalkyl)phosphinate, bis(pentafluoroethyl)phosphinate,bis(nonafluorobutyl)phosphinate, (fluoroalkyl)phosphonate,(pentafluoroethyl)phosphonate, (nonafluorobutyl)phosphonate,nonafluorobutane sulfonate (nonaflate) (NFS), trifluoromethanesulfonate,trifluoroacetate, methanesulfonate, butanesulfonate, butylsulfate,hexylsulfate, octylsulfate, dicyanamide, tricyanomethide, thiocyanate,hydrogensulfate, trifluoroacetate, tosylate, (bis(2-2-ethyl hexyl)sulfosuccinate (AOT), naphthenates, lauryl sulphate, alkyl benzenesulfonates, alkyl naphthalene sulfonate), alkyl aryl ether phosphates,alkyl ether phosphate, alkyl carboxylates, wherein “alkyl” isC₁-C₂₀alkyl, “fluoroalkyl” is fluorinated C₁-C₂₀alkyl, “perfluoroalkyl”is C₁-C₂₀ perfluoroalkyl, and “aryl” is optionally substitutedC₅-C₈-aryl.
 7. A formulation according to claim 1, characterized in thatthe conductive additives are selected from ionic organic compoundscomprising one or more polymerisable functional groups.
 8. A formulationaccording to claim 1, characterized in that the conductive additives areselected from formula 1:P¹-Sp-C⁺A⁻  1 wherein P¹ is a polymerisable group, Sp is a spacer groupor a single bond, C⁺ is a cation, and A⁻ is an anion.
 9. A formulationaccording to claim 8, characterized in that the conductive additives areselected from formula 1a-1c:P¹-Sp-[NR^(a)R^(b)R^(c)]⁺A⁻  1aP¹-Sp-[PR^(a)R^(b)R^(c)]⁺A⁻  1bP¹-Sp-[SR^(a)R^(b)R^(c)]⁺A⁻  1c wherein P¹, Sp and A⁻ are as defined inclaim 8, and R^(a), R^(b), R^(c) independently of each other denotestraight-chain, branched or cyclic alkyl with 1 to 25, preferably 1 to10 C-atoms, wherein one or more CH₂ groups are optionally replaced, ineach case independently from one another, by —O—, —S—, —NH—, —NR⁰⁰—,—CO—, —CH═CH— or —C≡C— in such a manner that O and/or S atoms are notlinked directly to one another, and wherein one or more H atoms may alsobe replaced by F, Cl, Br, I or CN, or two of R^(a), R^(b) and R^(c)together with the N⁺ atom form an aliphatic or aromatic ring with 4 to 8C atoms which is optionally substituted by one or more groups L, L isP¹-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰⁰R⁰⁰⁰,—C(═O)X, —C(═O)OR⁰⁰, —C(═O)R⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅, optionallysubstituted silyl, aryl or heteroaryl with 1 to 12, preferably 1 to 6 Catoms, and straight chain or branched alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12,preferably 1 to 6 C atoms, wherein one or more H atoms are optionallyreplaced by F or Cl, R⁰⁰, R⁰⁰⁰ independently of each other denote H oralkyl with 1 to 12 C-atoms, and X is halogen.
 10. A formulationaccording to claim 1, characterized in that the conductive additives areselected from organic compounds that comprise one or more polar groupsthat increase the conductivity of the RM formulation and one or morepolymerisable functional groups.
 11. A formulation according to claim10, characterized in that the conductive additives are selected offormula 2P¹-Sp³-G  2 wherein P¹ is a polymerisable group, Sp³ is an alkylenespacer with 2 to 12 C atoms, which is optionally substituted with one ormore groups G, and wherein one or more CH₂ groups are optionallyreplaced by —O—, —S—, —CO—, NR⁰⁰R⁰⁰⁰, or denotes a single bond, whereinR⁰⁰ and R⁰⁰⁰ independently of each other denote H or alkyl with 1 to 12C-atoms, and G is a polar group selected from COOH, OH, NH₂, NO₂, SO₃H,SH, PO₃H₂, and benzene that is mono- or polysubstituted with COOH, OH,NH₂, NO₂, SO₃H, SH or PO₃H₂.
 12. A formulation according to claim 1,characterized in that it comprises one or more polymerisable mesogeniccompounds having only one polymerisable functional group (monoreactive),and one or more polymerisable mesogenic compounds having two or morepolymerisable functional groups (di- or multireactive).
 13. Aformulation according to claim 1, characterized in that it comprises oneor more RMs of formula IP¹-Sp¹-MG-Sp²-P²  I wherein P¹ and P² are independently of each other apolymerisable group, Sp¹ and Sp² are independently of each other aspacer group or a single bond, and MG is a rod-shaped mesogenic group offormula II-(A¹-Z¹)_(n)-A²-  II wherein A¹ and A² denote, in case of multipleoccurrence independently of one another, an aromatic or alicyclic group,which optionally contains one or more heteroatoms selected from N, O andS, and is optionally mono- or polysubstituted by L, L is P-Sp-, F, Cl,Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)X,—C(═O)OR⁰⁰, —C(═O)R⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅, optionally substitutedsilyl, aryl or heteroaryl with 1 to 12, preferably 1 to 6 C atoms, andstraight chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,R⁰⁰, R⁰⁰⁰ independently of each other denote H or alkyl with 1 to 12C-atoms, X is halogen, preferably F or Cl, Z¹ denotes, in case ofmultiple occurrence independently of one another, —O—, —S—, —CO—, —COO—,—OCO—, —S—CO—, —CO—S—, —O—COO—, —CO—NR⁰⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰,—NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—,—OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—,—CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C≡C—,—CH═CH—COO—, —OCO—CH═CH— or a single bond, preferably —COO—, —OCO— or asingle bond, Y¹ and Y² independently of each other denote H, F, Cl orCN, n is 1, 2, 3 or 4, preferably 1 or 2, most preferably 2, n1 is aninteger from 1 to 10, preferably 1, 2, 3 or
 4. 14. A formulationaccording to claim 13, characterized in that it comprises one or moreRMs of formula Ia

wherein P⁰ is, in case of multiple occurrence independently of oneanother, a polymerisable group, preferably an acryl, methacryl, oxetane,epoxy, vinyl, vinyloxy, propenyl ether or styrene group, Z⁰ is —COO—,—OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—, —C≡C—, —CH═CH—, —OCO—CH═CH—,—CH═CH—COO—, or a single bond, L has the meanings given in claim 13 andis preferably, in case of multiple occurrence independently of oneanother, selected from F, Cl, CN or optionally halogenated alkyl,alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy oralkoxycarbonyloxy with 1 to 5 C atoms, r is 0, 1, 2, 3 or 4, x, y areindependently of each other 0 or identical or different integers from 1to 12, z is 0 or 1, with z being 0 if the adjacent x or y is
 0. 15. Aformulation according to claim 13, characterized in that it comprisesone or more RMs selected from the following formulae:

wherein P⁰, L, r, x, y and z are as defined in formula Ia.
 16. Aformulation according to claim 1, characterized in that it comprises oneor more RMs of formula IIIP¹-Sp¹-MG-R  III wherein P¹ is a polymerisable group, Sp¹ is a spacergroup or a single bond, and MG is a rod-shaped mesogenic group offormula II-(A¹-Z¹)_(n)-A²-  II wherein A¹ and A² denote, in case of multipleoccurrence independently of one another, an aromatic or alicyclic group,which optionally contains one or more heteroatoms selected from N, O andS, and is optionally mono- or polysubstituted by L, L is P-Sp-, F, Cl,Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)X,—C(═O)OR⁰⁰, —C(═O)R⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅, optionally substitutedsilyl, aryl or heteroaryl with 1 to 12, preferably 1 to 6 C atoms, andstraight chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,Z¹ denotes, in case of multiple occurrence independently of one another,—O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—, —CO—NR⁰⁰—,—NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰, NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—, —OCH₂—, —CH₂O—,—SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)_(n1),—CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰⁰—,—CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond, preferably—COO—, —OCO— or a single bond. Y¹ and Y² independently of each otherdenote H, F, Cl or CN, n is 1, 2, 3 or 4, preferably 1 or 2, mostpreferably 2, n1 is an integer from 1 to 10, preferably 1, 2, 3 or 4, Rdenotes P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,—C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)X, —C(═O)OR⁰, —C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅,optionally substituted silyl, straight chain or branched alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxywith 1 to 12, preferably 1 to 6 C atoms, wherein one or more H atoms areoptionally replaced by F or Cl, X is halogen, preferably F or Cl, andR⁰⁰ and R⁰⁰⁰ are independently of each other H or alkyl with 1 to 12C-atoms.
 17. A formulation according to claim 1, characterized in thatit comprises one or more RMs selected from the following formulae:

wherein P⁰, L, r, x, y and z are P₀ is, in case of multiple occurrenceindependently of one another, a polymerisable group, preferably anacryl, methacryl, oxetane, epoxy, vinyl, vinyloxy, propenyl ether orstyrene group L are independently of one another, selected from F, Cl,CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 Catoms, r is 0, 1, 2, 3 or 4, x, y are independently of each other 0 oridentical or different integers from 1 to 12, z is 0 or 1, with z being0 if the adjacent x or y is 0, R⁰ is alkyl, alkoxy, thioalkyl,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxywith 1 or more, preferably 1 to 15 C atoms which is optionallyfluorinated, or denotes Y⁰ or P—(CH₂)_(y)—(O)_(z)—, X⁰ is —O—, —S—,—CO—, —COO—, —OCO—, —O—COO—, —CO—NR⁰¹—, —NR⁰¹—CO—, —NR⁰¹—CO—NR⁰¹—,—OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—,—CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰¹—, —CF═CF—,—C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond, Y⁰ is F, Cl, CN, NO₂,OCH₃, OCN, SCN, SF₅, optionally fluorinated alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 4 Catoms, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 Catoms, A⁰ is, in case of multiple occurrence independently of oneanother, 1,4-phenylene that is unsubstituted or substituted with 1, 2, 3or 4 groups L, or trans-1,4-cyclohexylene, R^(01,02) are independentlyof each other H, R⁰ or Y⁰, u and v are independently of each other 0, 1or 2, w is 0 or 1, and wherein the benzene and napthalene rings canadditionally be substituted with one or more identical or differentgroups L.
 18. A formulation according to claim 1, characterized in thatit further comprises one or more organic solvents.
 19. A formulationaccording to claim 1, characterized in that it comprises 30 to 99.9% ofpolymerisable mesogenic compounds having two or more polymerisablefunctional groups, 0 to 90% polymerisable mesogenic compounds havingonly one polymerisable functional group, 0.01 to 5% of one or moreconductive additives, 0 to 5% of one or more surfactants, 0 to 5% of oneor more polymerisation initiators.
 20. A formulation according to claim19, characterized in that it comprises 50 to 80% of polymerisablemesogenic compounds having two or more polymerisable functional groups,10 to 70% polymerisable mesogenic compounds having only onepolymerisable functional group, 0.1 to 1% of one or more conductiveadditives, 0.1 to 1% of one or more surfactants, 0.1 to 2% of one ormore polymerisation initiators.
 21. A polymer film obtained bypolymerising an RM formulation according to claim 1, wherein the RMs arealigned and are polymerised at a temperature at which the RM formulationexhibits a liquid crystal phase.
 22. The use of an RM formulation orpolymer film according to claim 1 in an optical, electrooptical orelectronic device or in a component thereof.
 23. An optical,electrooptical or electronic device, or a component thereof, comprisingan RM formulation or polymer film according to claim
 1. 24. A componentaccording to claim 23, which is selected from optical retardation films,polarizers, compensators, beam splitters, reflective films, alignmentlayers, colour filters, antistatic protection sheets, or electromagneticinterference protection sheets, polarization controlled lenses forautostereoscopic 3D displays, and IR reflection films for windowapplications.
 25. A device according to claim 23, which is selected fromelectrooptical displays, especially liquid crystal displays,autostereoscopic 3D displays, organic light emitting diodes (OLEDs),optical data storage devices, and window applications.